Re: [amsat-bb] TZ6RD operation..

[Jerry Pixton <jpixton@xxxxxxxxxxx>]

Hi all,

As one who had to call twice because I got stepped on before I got a change 
to give my report.

It seems that several issues are evident.

One, split sounds like a good idea. On have we think nothing of 
transmitting in the blind while we listen to the DX signal - but even there 
you notice many stations still keep transmitting while the DX is replying - 
ie they are not listening either.  But on the satellite we have an 
additional problem.

1. We need to be using Full Doppler Tracking so that we can move way off 
frequency - like the low end of the band to adjust our transmitter. I 
notice in my setup that there are enough variables from day to day that the 
offset moves around over maybe 5Khz so we need to be able to hear 
ourselves. Then we must be able to lock in that offset so we can tune back 
up the band and have the transmitter automatically follow us. This implies 
a modern radio that can track. Then we can move our transmitter to the same 
uplink (here using the Birds transmit down link might be a better 
reference) eg 435.600 and then is the DX and my transmitter is on frequency

But if I work split (I have been playing with some split buttons to move 1, 
2, 3 KHZ etc off frequency) now I can not hear my own downlink signal or 
the interference at the same time I hear the DX station.
 From the other end as the DXer, split means I have to unlock the tracking 
offset, keep my transmitter doppler corrected (again maintaining the Birds 
downlink constant is a better strategy) while my receiver is tuning around 
listening for stations. Implies more equipment on the DX side.

So the practical side of "split" that works on HF seems to be harder on 
satellite. We can not even get people to hear themselves without causing 
interference.

Another thought, many we need some reserved DX frequency. When a station 
starts calling CQ and has several contacts right on the announced frequency 
of the DX causing the DX to move down out of the way.

Interesting problem. First we need to hear ourselves. Then we need to use 
Full Doppler Tracking. Then we do need to be polite and wait for exchanges 
to be completed.

Just you thoughts as one trying to implement a split mode.

Jerry, W6IHG




At 03:31 PM 8/19/2003 -0400, Jeffrey Griffin wrote:
>   I like the split idea, and the by the numbers routine myself. Exactly what
>you would use on HF in a pileup. Perhaps, by the numbers would be less
>confusing for everyone involved. Also I agree the Bali group should of asked
>for NA's, even NA ones, and two's first, or where ever the small closing
>window of opportunity was. So the in-experience is on both sides of the
>pileup. And of course people should have more sense then to find one's self
>right on the dxer's listening frequency. As there is about 400k of bandwidth
>on AO40 to find one's downlink. Another problem on AO40 is everyone calling
>is closer to the same signal strength , more so then on HF.






------------------------------------------
Dr. Jerry R. Pixton, PIXOS Designs LLC
http://www.pixos.com/designs/RadioTuner/
jpixton@shentel.net
------------------------------------------


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